Much like the roofs of houses and warehouses, a car roof is just empty space, so why not hook up some solar cells to the latest hybrids? Solar Electrical Vehicles is looking to do just that with a solar roof module for hybrid cars. The cost is about $2000-$4000 for a supplemental battery and solar module rated at 200-300 watts. For the Prius this adds up to 20 miles per day of electric mode driving with higher-capacity batteries adding another 10 miles.

Modules in production work with the Toyota Prius, Highlander and RAV4 EV, Ford Escape Hybrid and Dodge Sprinter Hybrid. In the future they hope to integrate them with Teslas and upgrade to a 320-watt module, up from 212-watts currently.

While not adding a whole lot of economic benefit to hybrid cars, it’s an easy solution for people looking to squeeze more juice out of them. Unlike solar additions in homes, hybrid cars have the technology already built in to benefit from a solar add-on making them a simple installation.